JP3216878B2 - Grout material for ground injection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grouting material for ground injection, which is used particularly for prevention of liquefaction of the ground, excavation work of urban civil works, reinforcement of foundations, and waterproofing work of dams. The present invention relates to a grout material for injecting ground, which has excellent properties, good durability, high consolidation strength, and low pollution.

[0002]

2. Description of the Related Art Activated silicic acid having a pot life of about 1 to 3 days obtained by treating water glass with an ion exchange resin has been widely used for the purpose of improving soft ground. (See Japanese Patent Application No. 9-183239). Further, acidic water glass obtained by mixing water glass and an acid is widely used.

[0003]

Generally, active silicic acid is a substance produced by treating water glass with a cation exchange resin to replace Na ⁺ of water glass with H ⁺ and exhibiting a pH of 2 to 4.

In the production of active silicic acid, if the silica concentration (SiO ₂ concentration) of the water glass is high, the water glass gels while passing through the cation exchange resin. For this reason, SiO
_{2 The} concentration is at most around 6% and the gel time is at most 2 to 3 days at room temperature.

[0005] Although such active silicic acid exhibits extremely excellent durability, it gels in a few days, so it easily gels during transportation from the factory to the site, and particularly when the temperature is high. At times or when the SiO ₂ concentration is high, gelation is rapidly promoted, and the gelation occurs even when the on-site construction has been waited for a long time, making it unusable. That is, since active silica cannot increase the concentration of SiO ₂ , high strength cannot be expected. Also,
Acidic water glass is made by making highly alkaline water glass into a strongly acidic region, which is a stable gelation region, and adding an alkali material to the mixture to shorten the gelation time . In order to achieve this, a large amount of a strong acid such as sulfuric acid must be used, and the injection solution contains many acid radicals. In addition, when an alkali material is added, the gel time fluctuates rapidly, and it is difficult to adjust the gel time. That is, there was a problem in terms of water quality conservation work.

Accordingly, an object of the present invention is to improve not only the durability but also the solidification strength and the permeability, which can prevent pollution and to improve the above-mentioned disadvantages of the prior art. It is to provide a grout material for injection.

[0007]

According to the present invention, there is provided, in accordance with the present invention, an active silicic acid obtained by treating a water glass with a cation exchange resin, an acidic material, a water glass,
It is characterized by comprising a pH value in an acidic to neutral range, which contains as an active ingredient , an active ingredient such as, for example, a toroidal silica .

[0008] The present invention further provides, in addition to the aforementioned active ingredients,
Thus, a gelling agent can be contained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The active silicic acid used in the present invention is obtained by treating water glass with a cation exchange resin to remove the alkali in the water glass, is substantially free of salts, and has a molecular weight of 1,000 or less. And has a pH of about 2 to 4 and a pot life of about 1 to 3 days. This pot life depends somewhat on the pH and the SiO ₂ concentration.

The water glass used here is water glass having an arbitrary molar ratio, but practically JIS No. 3 water glass is generally used. In the present invention, activated silicic acid can be produced by using a water-soluble silicate such as potassium silicate or ammonium silicate instead of water glass.

The acidic material used in the present invention is hydrochloric acid, sulfuric acid,
Inorganic acids such as phosphoric acid, aluminum chloride, sodium hydrogensulfate, inorganic acid salts such as sodium acid phosphate, etc., which dissolve in water to exhibit acidity, organic acids such as tartaric acid, lactic acid and acetic acid, and organic acid salts such as sodium hydrogen tartrate And so on.

The content of the acidic material in the activated silicic acid is very small as compared with the amount used in the conventional acidic water glass, and the usable time of the obtained grout material is greatly increased. The lower the pH value of activated silicic acid is caused by adding an acidic material, the longer the pot life becomes. growing. Furthermore, since the gelling time is greatly extended with a small amount of the acidic material, the amount of acid radicals can be reduced, and the water quality of groundwater is excellent. In addition, even if a weak acid such as phosphoric acid or an organic acid is used, the gelation time is easily extended, so that it is not necessary to use a strong acid such as sulfuric acid, so that the handling is easy, and the amount of the gelled time is short. Since no sharp change is caused, the gel time can be easily adjusted.

As described above, the grout material according to the present invention, in which the active life is extended by adding an acidic material to activated silicic acid, further comprises water glass and / or colloidal silica.
An alkaline material (hereinafter, simply referred to as an alkaline material) is added, and the pH is adjusted to an acidic to neutral region to adjust the gelation time. Effect described above of water glass and colloidal silica to increase the strength of the SiO ₂ by increasing the concentration caking of grout
Present.

[0015] The present invention further comprises the use of a gelling modifier.
Can be. Sodium aluminate is used as this gelling agent.
Da, baking soda, sodium carbonate, sodium bicarbonate, limes, etc.
Is mentioned.

Further, various salts may be used as the gelling agent.
No. Examples thereof include chlorides such as sodium chloride and potassium chloride, phosphates such as sodium hydrogen phosphate, and sequestering agents such as sodium hexametaphosphate.

The amount of the alkaline agent used varies depending on the gelation time of the obtained grout material. In an amount such that the pH value of the grout material exhibits a pH of 6 or less, a long-lasting gelation time is obtained, and in an amount such that the pH value exhibits a nearly neutral pH around 6 to 8.5, A short gelling time is obtained.

Further, according to the present invention, the water silicide is added to the grout material having a longer pot life by adding an acidic material to activated silicic acid.
The gelation time is shortened by adding an alkali material composed of silica and / or colloidal silica and then moving to an almost neutral region. Water glass and colloidal silica are not solution type
The strength of the solidified body is increased.

Activated silicic acid, acid, water glass and / or
Although the method of mixing colloidal silica varies depending on the pH and the liquid volume ratio, any method may be used as long as mixing is easy and the pH exhibits an acidic-neutral region . For example, live
It is preferable to add an alkali material to the silicic acid and the acid in a short time while strongly stirring the acid .

The grout material of the present invention may be compounded on site.
However, adjust the activated silicic acid containing acidic material at the factory or adjust it so that it does not gel during transport to the site or during storage at the site, and mix the alkali material at the site to prevent work problems Can be.

According to the present invention obtained as described above.
Grout material contains active silicic acid, so it is better than conventional water glass.
Since even the alkali amount is small, only a use amount of the reaction agent is also reduced. For this reason, only a small amount of salt is eluted from the grout material of the present invention into groundwater, which is excellent in terms of water quality conservation.

When cement is used as a reactant,
In this case , the durability of the obtained consolidated body is improved, and the strength is also increased. However, for the purpose of preventing liquefaction , grout material
When injecting into the ground, permeability and durability of the consolidated body are required. In such a case, alkaline
The grout material can be used by adding an acid material to the grout material and transferring it to the acidic region again. As described above, it is possible to make the active silicic acid freely acidic or alkaline, etc., because the alkali content in the active silicic acid is small and almost no salt generated by the neutralization reaction is contained.

When acidifying ordinary water glass, special equipment and mixing means are required, and the generated acidic silica sol contains a large amount of salts generated by neutralization. Is also not preferred. Moreover, in this case, not only the gelation time cannot be lengthened, but also the compact (gelled product) is greatly shrunk by syneresis water.

On the other hand, the grout of the present invention is an improvement over the above-mentioned disadvantages, in which the compaction strength is enhanced, the compact is hardly shrunk, the durability is excellent, and the gelation time is wide over a wide range. It can be adjusted and therefore has good permeability.

[0025] The active silicic acid itself obtained water glass was treated with the cation exchange resin although gel time exhibits a 1-3 days, rapidly gel time to shorten when injected into the ground, For example, a penetrating effect suitable for preventing liquefaction cannot be obtained. On the other hand, the grout of the present invention has a long gelation time and maintains a sufficiently long gelation time even in the ground. Moreover, the present invention grout, compared to the strong conventional water glass type grout alkalinity is adjusted to an acidic to medium of the region, and order to those containing a small amount of a salt is injected, alkali pollution and acid It does not cause pollution and has excellent water quality conservation.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

(Materials Used) Water glass Specific gravity (20 ° C) 1.39, SiO ₂ 29.0%, JIS3
No. water glass is used.

2. Activated silicic acid 17.5% water glass aqueous solution passed through a cation exchange resin, pH 2.7, specific gravity 1.03, SiO ₂ 5.0
% Active silicic acid is used. Gelation takes 1.5 to 2 days at room temperature.

3. Acidic materials Hydrochloric acid, sulfuric acid and phosphoric acid as inorganic acids, aluminum chloride and sodium hydrogen sulfate as inorganic acid salts, tartaric acid as organic acid, and sodium hydrogen tartrate as organic acid salt.

(1) Hydrochloric acid: Reagent primary HCl (2) Sulfuric acid: 75% industrial sulfuric acid H ₂ SO ₄ (3) Phosphoric acid: 75% industrial phosphoric acid H ₃ PO ₄ (4) Aluminum chloride: Reagent First grade, hexahydrate AlCl ₃・
6H ₂ O (5) Sodium hydrogen sulfate: Reagent first grade, NaHSO ₄ .H
₂ O (6) Tartaric acid: primary reagent, COOH.CH (OH) CH
(OH) .COOH (7) Sodium hydrogen tartrate: First-class reagent, COOH.CH
(OH) CH (OH) .COONa.H ₂ O

4. Alkali material Colloidal silica, cement, water glass, sodium carbonate, and sodium bicarbonate are used.

(1) Colloidal silica After passing a water glass aqueous solution through a cation exchange resin,
An alkali is added thereto, and the mixture is heated and polymerized.
_{O 2: ~30~31%, Na 2} O: 0.7% or less, a specific gravity:
A colloidal solution of silicic anhydride having a pH of 9 to 10 and a pH of 9 to 12 is used.

(2) Cement: Portland cement is used.

(3) Water glass No. 3 water glass is used.

(4) Sodium carbonate Anhydrous sodium carbonate, first grade reagent, Na ₂ CO ₃ is used.

(5) Sodium hydrogencarbonate First grade reagent, NaHCO ₃ is used.

Example 1 Preparation of Active Silicic Acid Each sample having the composition shown in Sample Nos. 1 to 17 in Table 1 was prepared, and the pH, the gel time at 20 ° C., and the shrinkage of the homogel were determined for each sample. The measurement was performed and the results are shown in Table 1. In Table 1, Sample No. 1 is a sample containing only activated silicic acid,
Sample Nos. 2 to 17 are grout materials (active silicic acid containing an acidic material) according to the present invention with a longer pot life.

[0038]

[Table 1]

The following can be seen from Table 1. Sample No. 1 was activated silicic acid itself containing no acidic material, and had a gelation time of 1.5 to 2 days.

On the other hand, the samples Nos. 2 to 17 according to the present invention containing an acidic material exhibit a gelation time of 3 to 7 days, respectively, and the pot life is extended.

Of these, Sample No. 2 (sulfuric acid), Sample No. 3 and Sample No. 4 using an inorganic acid or an inorganic acid salt as an acidic material
(Phosphoric acid), sample Nos. 5 to 8 (hydrochloric acid), sample No. 11 (aluminum chloride), samples Nos. 13 and 14 (hydrochloric acid and aluminum chloride) exhibit a gelation time of about 3 to 4 days. Particularly, in Sample No. 4 in which phosphoric acid was used as an acidic material and the pH was lowered to 1.4, the gelation time was extended to 4 to 5 days.

Sample Nos. 9 and 10 (tartaric acid) and Sample No. 12 (sodium bitartrate) using an organic acid, an organic acid salt, or an organic acid and an inorganic acid salt or an organic acid salt as the acid material. , Sample Nos. 15 to 17 (combined use of hydrochloric acid, tartaric acid, aluminum chloride, sodium hydrogen tartrate, etc.) all had a gelation time extended to 5 to 7 days despite their relatively high pH values.

Further, in the sample No. 1 of Table 1, the shrinkage ratio of the homogel was about 20%, whereas the sample according to the present invention was
In Nos. 2 to 17, the shrinkage ratio of the homogel is as small as 10 to 13%, although the gelation time is prolonged.

It should be noted that each of the sample No. 2 (combination of activated silicic acid and sulfuric acid) in Table 1 and a conventionally known acidic water glass (combination of ordinary water glass and sulfuric acid) not shown in Table 1 were both used. After adjusting the SiO ₂ concentration to 5-5.2% and the pH value to 2.1 and comparing the amount of sulfuric acid used, Sample No. 2 showed 0.1%.
3 g, but the acid water glass weighed 3.5 to 4 g.
From this, it can be seen that Sample No. 2 according to the present invention is a grout material in which the acid radical is significantly reduced as compared with the conventional acidic water glass. In addition, the gel time of sample No. 2 according to the present invention was extended for 3 to 4 days, whereas that of the conventional acidic water glass was 20 to 40 hours.

2 Preparation of Grout Material Made by Adding Alkali Material to Activated Silicic Acid Containing Acid Material 6, that is, activated silicic acid containing hydrochloric acid as an acidic material; 10, that is,
Various alkali materials shown in Table 2 were blended into activated silicic acid containing tartaric acid as an acid material. 18-33 were prepared. For each of these samples, the pH, the gel time at 20 ° C., the uniaxial compressive strength of the sand gel (kgf / cm
² ) and the shrinkage (%) of the homogel were measured, and the results are shown in Table 2. The unconfined compressive strength of the sand gel is as follows.
Days and after 8 days, the unconfined compressive strength of sand gel (kg
f / cm ² ).

[0046]

[Table 2]

Table 2 shows the following. In Sample Nos. 18 to 21 (using water glass as the alkali material) using Sample No. 6 in Table 1 as the active silicic acid, the gelation time was shortened with an increase in pH, and the consolidation strength was also increased. Also,
In Sample Nos. 25 to 27 (colloidal silica was used as the alkali material), the consolidation strength was further improved. further,
Sample No. 22 (both water glass and colloidal silica were used as the alkali material) also had an increased consolidation strength. Sample No. 2 using Sample No. 10 of Table 1 as active silicic acid
8 to 32 (water glass, colloidal silica, or both of them are used as the alkali material) show the same tendency as described above. In these samples, the gelation time can be adjusted over a wide range of pH from acidic to neutral .

Although not shown in Table 2, the water glass-sodium bicarbonate sample (control) in which the SiO ₂ concentration was almost the same as each sample in Table 2 and the gelation time was adjusted to one to several minutes was used. After several days of curing, the solidification strength of sand gel is 0.6-1.
It is about 0 kgf / cm ² . On the other hand, in Samples Nos. 18 to 22 and 25 to 32 according to the present invention, particularly, in Sample Nos. 28 to 32 in which the pot life was extended by tartaric acid, the strength was further increased more than the control sample. Have been.

Although the control sample is not shown in Table 2, it is known that the shrinkage of the homogel reaches up to about 25%. As shown, the shrinkage of the homogel is 15% or less.
In particular, sample N in Table 2 using colloidal silica as the alkali material and sample No. 10 in Table 1 as the active silicic acid
In o.30 to 31, the shrinkage rate is 5% or less, which is very small.

In Table 2, in samples No. 23, 24 and 33 using cement as the alkali material, the high consolidation strength peculiar to cement is sufficiently exhibited. In particular, the strength of 8 days of curing is significantly higher than the initial strength, and is excellent in long-term strength. Although not shown in Table 2, the use of finely divided cement in the present invention is expected to significantly increase the strength. Also,
In the present invention, slag can be used in combination.

3 Preparation of Grout Material Made of Activated Silicic Acid Only or Active Silicic Acid Containing an Acidic Material Added with an Alkaline Material Sample No. 1 (active silicic acid alone) and Sample No. 6 in Table 1 (hydrochloric acid as an acidic material) Each of the alkali materials shown in Table 3 was added to the sample No. 10 (active silicic acid containing tartaric acid as an acidic material) and the sample No. 10 (active silicic acid containing tartaric acid as an acidic material) to prepare grout materials of Sample Nos. 34 to 43. The pH and curability (gelation time) of each of these samples were measured, and the results are shown in Table 3.

[0052]

[Table 3]

Table 3 shows the following. That is, when an alkaline material is added to activated silicic acid to shift the pH value to an alkaline region (pH 8.5 or more), a grout material that does not cure for a long period of time and is stable for a long period of time is obtained. Further, when the pH value is made neutral or slightly alkaline (pH of about 8.5 or less) as in Sample No. 34 and Sample No. 39, gelation occurs.

4 Preparation of Grouting Material for Ground Injection Using Activated Silicic Acid with Extremely Long Working Life The sample Nos. 36, 37, 38, 41, 42, and 43 in Table 1 (each having a significantly long working life) were used. As shown in Table 4, each sample was prepared by adding sodium hydrogen sulfate as an acidic material.
o.44-51 were prepared. About these samples, pH,
The gelation time at 20 ° C., the uniaxial compressive strength of the sand gel, and the shrinkage of the homogel were measured, and the results are shown in Table 4.

In Table 4, the uniaxial compressive strength of the sand gel is shown in Table 2.
As in the above, the strength (kgf / cm ² ) was measured after the sand gel of Toyoura standard sand was hermetically sealed in a polyvinylidene chloride bag for 1 day and 8 days. The homogel contraction rate is 3
Shrinkage rate (%) after elapse of 30 days and 30 days.

[0056]

[Table 4]

Table 4 shows the following. Activated silicic acid (for example, sample Nos. 36, 37, 38, 41, 42, and 4 in Table 3) having been transferred to an alkaline region to significantly increase the pot life.
3) can be gelled by adding a reactant (acidic material) to each of them. Moreover, all of them show higher strength than ordinary water glass grout. Furthermore, the shrinkage of the homogel is at most 10%.
About 20% of normal water glass grout. In particular, sample No. 47 using tartaric acid as an acidic material seems to be slightly superior in both strength and shrinkage ratio to samples No. 46 and 50 using hydrochloric acid.

In each of the samples shown in Table 4, the amount of sodium hydrogen sulfate added as a reactant (acid material) was 0.3 to 0.3.
Although it is in the range of 4 g, about ₂ g of water glass No. 3 having almost the same SiO ₂ content can be gelled with sodium hydrogen sulfate.
~ 3 g addition is required. That is, in the present invention,
The amount of the reactant used is significantly smaller than that of a conventional water glass grout. Therefore, in the present invention, the elution of acid radicals or other salts from the gelled material after the ground injection is extremely small, which is preferable from the viewpoint of water quality conservation.

In Tables 1 to 4 in the above Examples, the pH value was measured by a glass electrode pH meter, the gel time was measured by a cup inversion method, and the uniaxial compressive strength was measured according to the standard of the Japan Society of Soil Engineers, "Uniaxial compressive test method for soil". The shrinkage ratio of the homogel was calculated from the amount of synergic water released after the homogel was cured in a closed container made of polypropylene resin.

5 Gelation Test in Soil As shown in Table 5, sample No. 1 in Table 1 1 (active silicic acid alone) samples of Table 1 No. 6, Sample No. 1 in Table 1. 15,
In Table 1, the sample No. 16, sample no. 18 and Table 4 sample no. Samples 44, respectively No. 5 was prepared as 2-57. Each of these samples was mixed with Toyoura standard sand at a temperature of 20 ° C., and after standing still, a bamboo skewer was stabbed in the sand and pulled out. Table 5 shows the results.

[0061]

[Table 5]

Table 5 shows the following. Sample No. 52 is a sample No. 1 in Table 1 and had a pH of 2.7 and a gel time of 1.5 to 2 days as shown in Table 1 before mixing with sand. As shown in Table 5, after mixing with, the gelling time in soil was reduced to 30 minutes. In order to prevent liquefaction of the soil, it is necessary to further lengthen the gelation time to achieve sufficient permeation.

In the case of sample Nos. 53 to 57,
Even after the mixing with sand, the gelation time is shortened, but is still as long as about one hour or several tens of hours, and the gelation has been completely achieved. Therefore, it is presumed that these samples exert extremely good effects as a liquefaction-preventing grout material.

6. Viscosity It was found that all the samples according to the present invention according to the above-described examples had a viscosity lower than that of a conventional water glass grout, although it was qualitatively observed, but immediately before gelation. In particular, the viscosity of a sample containing an organic acidic material is extremely low.

[0065] From the above, the active silicic acid as a main material, to which acid
The grout material according to the present invention, in which a grout material and an alkali material are blended, can have a long pot life as a grout material, and it is relatively easy to adjust the gel time, including gelling in soil. Furthermore, compared to conventional water glass grout, the viscosity before gelation is low, and the gel has high strength and low shrinkage, so that it can be expected to be excellent in permeability, durability and liquefaction prevention.
Further, it is possible to reduce the alkali pollution problem which is a concern in the conventional water glass grout.

[0066]

[Effect of the Invention] The active silicic acid as a main material, to which acid and alk
The grout material according to the present invention in which the wood material is blended has the following effects.

1. A grout material with a long pot life can be prepared.

2. Grout can be prepared over a wide range of gelation times, including soil gelation.

3. A high-strength, low-shrinkage compact is obtained, and the grout material has low viscosity.

4. Therefore, the grout material of the present invention can be expected to have excellent permeability, durability and liquefaction prevention.

5. Activated silicic acid using an organic acidic material is particularly excellent in the above effects.

6. We can expect reduction of alkaline pollution.

7. Less elution of salt from gelled material and excellent water quality conservation.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C04B 111: 70 C04B 111: 70 C09K 103: 00 C09K 103: 00 (56) References JP-A-11-172248 (JP, A) JP-A-60-144382 (JP, A) JP-A-60-20992 (JP, A) JP-A-6-330037 (JP, A) JP-A-11-61124 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C09K 17/00-17/52 C04B 28/00-28/36 E02D 3/00-3/12

Claims (2)

(57) [Claims] An active silicic acid obtained by treating a water glass with a cation exchange resin, an acidic material, a water glass, and a colloidal material.
A grout material for injection into the ground, which contains rusilica as an active ingredient and exhibits a pH value in an acidic to neutral range. 2. The grout material for injecting ground according to claim 1, further comprising a gelling agent.